Tobramycin and gentamicin are equally safe for neonates: results of a double-blind randomized trial with quantitative assessment of renal function

Abstract

The frequent use of aminoglycosides in neonates led us to compare tobramycin and gentamicin because some studies in adults and animals suggested a safety advantage for tobramycin. In a randomized, double-blind comparison, 50 infants < or = 3 days old received either tobramycin or gentamicin, 2.5 mg/kg/12 hr, for a mean of 8 days. The groups were similar for gestational age, birth weight, underlying disease, Apgar score, clinical condition, renal function, and concurrent use of other drugs. Trough and postdose serum concentrations of both drugs were similar in each weight group. Renal status at onset, during or up to 2 wk after therapy was also similar, as judged by urinalysis, serum creatinine, fractional excretion of Na, urine N-acetyl-beta-glucosaminidase, and urine to serum creatinine ratio. Nephrotoxicity occurred in four infants (13%) receiving tobramycin and three infants (15%) receiving gentamicin. No otoxicity, as measured by auditory brainstem response, was noted in either group. Tobramycin offered no safety advantages over gentamicin in neonates, and the choice between the agents should be based on other considerations, such as susceptibility of the pathogen and cost.